I. Caribbean Region (of South America)

The coastal area of northern Colombia and Venezuela is phytogeographically distinct
from the rest of South America and more closely related floristically to Central America
and the West Indies. The region includes the Cordillera de la Costa of Venezuela as well
as the Llanos savanna grasslands, and the strongly seasonal lowland forests bordering the
Caribbean coast. The latter includes a small area of dry thorn scrub in the most northern,
driest part of the region on the Guajira Peninsula. The area north of the Orinoco River is
open savanna interrupted by gallery forests along the major rivers, and is
phytogeographically completely different from adjacent Amazonia. The region is delimited
to the south by the Orinoco and its major Colombian tributary the Guaviare, and to the
west the limit is the 500 m contour of the Andean Cordillera Oriental. The division
between the Andes proper and the Coastal Cordillera is not the Colombia/Venezuela border,
but near the Yaracuy Depression; thus the uplands of Táchira, Mérida and Trujillo states
of Venezuela are included in the Andean region.

Around the northern margins of the Central Andean and Western Andean cordilleras in
Colombia, delimitation of the Caribbean region from the Andes and from the western
Colombian Chocó region is more complicated. West of the Sinu River and especially in the
Atrato Delta region, the Caribbean coastal area is much less seasonal and
phytogeographically might more appropriately be included in the Chocó region. The
vegetation of much of the central Magdalena Valley of Colombia is also humid moist and wet
forest and has phytogeographical affinities with both the Chocó and Amazonia. There is a
significant endemic element in the moist part of the Magdalena, which also includes a
large swampy zone with several distinctive floristic elements. However the upper Magdalena
Valley is strongly seasonal dry forest and phytogeographically a part of the Caribbean
coastal region. The wet-forest part of the Magdalena Valley and the adjacent Nechi area
are referred to the Pacific Coast region, whereas the bulk of the Magdalena Valley up to
1000 m in elevation and south to Neiva at 3°N latitude is included in the Caribbean
region. The narrower dry interior Cauca Valley can similarly be referred to the Caribbean
region.

The Caribbean region of South America as a whole has perhaps 6000 angiosperm species
and a relatively low regional endemism estimated at 24% (Gentry 1982a). This is by far the
lowest level of regional endemism of the neotropical phytogeographic regions recognized by
Gentry (1982a). The lowland forests of the Caribbean region are highly seasonal and not
very diverse botanically. Similarly the Llanos have very little endemism, unlike their
physiognomic counterpart the cerrado.

The Cordillera de la Costa, geologically not a part of the Andes, is geographically in
essence an Andean outlier, but floristically may be more similar to Central America. There
are also some disjunctions with Guayana and Amazonia (Steyermark 1982). This mountainous
region has a more diversified flora and a significant complement of endemic species,
estimated at 10%. Endemism and species richness are both concentrated in the wet montane
areas. A hint of the floristic richness comes from the Florula of Cerro Avila above
Caracas (Steyermark and Huber 1978), which includes 1892 species of vascular plants. This
is the most species contained in any similar Florula, but the data are not strictly
comparable, since the Avila Florula covers several different vegetation zones.

Most of the flora of the region is shared with that of Central America, and there seems
little doubt that there must once have been more or direct connections between the
seasonally dry forests of coastal Colombia and Venezuela and those of western Central
America. There are also several small areas on limestone hills near the coast (e.g.
Coloso, Colombia) which have a few taxa of distinctly Caribbean affinities, such as Buxus.

The indigenous peoples of the dry Caribbean coastal region eat the fruits of a variety
of local species including Bactris gasipaes, Chrysobalanus icaco, Geoffroea and Acrocomia.
In moister regions Gustavia superba is a familiar native species with an edible
fruit. In more upland forests of the Sierra Nevada de Santa Marta, the wild-harvested
fruits of Metteniusa edulis ("cantyi") and Pouteria arguacoensium
("manzana") are dietary staples (Cuadros 1990). The coastal region also has many
tree species with useful wood, including both widespread taxa like Cordia alliodora,
Aspidosperma polyneuron, Tabebuia rosea, and endemic species like Tabebuia
billbergii - the national tree of Venezuela (Cuadros 1990; Gentry 1992a).

The coastal areas of northern Colombia and Venezuela have been intensively occupied,
following the arrival of the first European colonizers in the early 16th century. They are
now very densely populated, and have some of the largest cities of the region (Caracas,
Maracaibo, Cartagena). The main impact on the flora and vegetation has been caused by
shifting cultivation and large-scale deforestations for agricultural and urban purposes.
In general the entire region is heavily affected, especially at lower elevations, but
there are still some remnants of montane cloud forests protected in several National Parks
and Natural Monuments.

The survival of representative and viable samples of arid vegetation in north-eastern
Colombia and northern Venezuela is being heavily affected by large-scale conversion into
agricultural lands, selective timber extraction - especially boles of certain arborescent
cacti for furniture, and browsing by goats. Dry forests are threatened by logging and
deforestation for pasture and agricultural lands.

Most of this region has been devastated by human activity. The situation is especially
critical in northern Colombia, where the largest patches of remnant natural vegetation
include rather few km. The shining exception is the dry forest (not the moist forest which
is mostly secondary) of Tayrona Natural National Park (Rangel-Ch. and Lowy-C. 1995) on the
north flank of the Sierra Nevada de Santa Marta (CPD Site SA25); this is one of the best
preserved dry forests in the neotropics and deserves more international conservation
attention. (In contrast, the nearby Salamanca NNP protects mostly dead mangroves, killed
as a result of construction of the coastal highway.)

In Venezuela six National Parks encompassing almost 5000 km² protect coastal and
insular ecosystems along the Coastal Cordillera, and eight National Parks encompassing
some 5130 km² protect more mountainous parts of the entire Coastal Cordillera between
Paria and San Luis, although some of them have largely second-growth vegetation.
Especially significant is Henri Pittier NP (established 1937 - one of the early National
Parks in Latin America), which includes not only an area of rich cloud forest but also a
transect of Caribbeanslope dry forest.